1. Field of the Invention
The present invention relates to a thin film transistor substrate, a method of manufacturing the same and a liquid crystal display having the same. More particularly, the present invention relates to a thin film transistor substrate manufactured through a 3-sheet mask process, a method of manufacturing the same, and a liquid crystal display having the same.
2. Description of the Related Art
A liquid crystal display (“LCD”) has advantages of a smaller size, a lighter weight and a larger display screen in contrast to a conventional cathode ray tube (“CRT”). As such, recent development of the LCD has been actively made. LCDs have been used as monitors for laptop and desktop computers, large-sized displays, and displays for mobile communication terminals. The applicable range of their utility is increasingly extending. In such an LCD, light transmittance is controlled by image signals applied to a plurality of control switches arranged in a matrix pattern, thereby displaying a desired image on a panel of the LCD.
To manufacture a thin film transistor substrate for an LCD in the prior art, five or four sheets of masks are generally required. Referring to FIG. 1, a flowchart illustrating a method for manufacturing a thin film transistor substrate through a 5-sheet mask process according to the prior art is shown. Five sheets of masks are required in total in such a manner that a first mask is required in step S10 of forming a gate pattern, a second mask in step S30 of forming an active layer pattern, a third mask in step S40 of forming a source/drain pattern, a fourth mask in step S70 of forming a protection film, and a fifth mask in step S80 of forming pixel electrodes.
In line with a desire to reduce production costs and improve productivity with respect to manufacturing a thin film transistor substrate for an LCD, current research on simplifying the current method of manufacturing a thin film transistor substrate is continuous. Accordingly, a method capable of simplifying manufacture of a thin film transistor substrate using less than 5 or 4 masks without changing the existing production lines is desired.